Wrapped edge manufacturer&#39;s joint



July 22, 1969 J. w. MoLLlsoN ETAL 3,456,863

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United States Patent O M' 3,456,863 WRAPPED EDGE MANUFACTURERS JOINT James W. Mollison, Lafayette, and Robert L. Cain, West Lafayette, Ind., assignors to Inland Container` Corporation, Indianapolis, Ind., a corporation of Indiana Filed June 14, 1967, Ser. No. 646,035

Int. Cl. B65d 5/42 U.S. Cl. 229-48 16 Claims ABSTRACT F THE DISCLOSURE Manufacturers joint for a waterproof corrugated fibreboard container constructed of a blank of corrugated breboard having spaced liners having liquid barrier coatings and corrugating medium therebetween, the blank having overlapping joint ends, each end of which comprises inner and outer liner portions extending beyond the corrugating medium, with at least one liner portion offset into contact with the other over a substantial area and adhesively secured thereto, the inner liner portions of .the inside lapping end being longer than and wrapped around the outer liner and overlying and adhesively secured over a substantial area of the other side of the outer liner, and the inner liner portion of the other end being adhesively secured to the overlying portion of the inner liner of the inside lapping end.

This invention relates to corrugated fibreboard containers for packaging or containing fluids or powders and the like; and more particularly to fluid-tight or leak-free seams or manufacturers joints, so-called, in such containers.

Corrugated fibreboard shipping containers are typically made from a rectangular blank of sheet material having right and left end margins, the ends of which blank are brought into close proximity with each other when the blank is folded along provided score lines. A manufacturers joint or seam is normally employed to fasten the original blank ends together in a manner permitting the formed container blank to serve as a useful shipping container.

Conventional manufacturers joints used in common corrugated fibre shipping containers normally comprise a taped joint in which the two original ends of the container blank are typically held together with a strip of remoistenable gummed paper tape or synthetic fibre reinforced gummed paper tape, or a stitched joint in which the two original ends of the container blank overlap and are held together by clinched metallic wire staples or stitches, or a glued joint similar to the stitched joint but held together by adhesive between the contacting plies of the overlapped ends in the manufacturers joint or seam.

The aforesaid types of manufacturers joint are very serviceable and useful on corrugated fibre shipping containers intended to be used for shipment of dry and solid commodities under normal commercial conditions.

Such joints are not serviceable in liquid-tight containers designed to contain and transport fluid or liquid products, for such joints or seams leave raw or unprotected paperboard fibres comprising the containerboard structure exposed to the fluid load to be contained. Such raw and unprotected paperboard fibres are normally quickly degraded and lose necessary strength and rigidity 4on exposure to liquid.

To make paperboard packaging into liquid-tight containers serviceable for containing, shipping, and storing liquid and fluid products, the present invention is directed toward preventing the degradation and destruction of the liquid-tight containers by preventing entry of liquid 3,456,863 Patented July 22, 1969 ICC into the paperboard structure at the manufacturers joint or seam area of the container.

A further object of the invention is to wrap the exposed edges to seal off the interior of the corrugated fibreboard packaging material. By wrapping the edges exposed to liquid, the entry of water or 'other liquid deleterious to the paperboard structure is prevented.

Suitable liquid-tight or leak-free manufacturers joints or seams may be constructed by wrapping the raw unprotected ends of a breboard sheet in the joint area by using any suitable flexible barrier material. The raw unprotected edges may be wrapped by a separate strip of thermoplastic flexible packaging film material, such as polyethylene film and the like. When such wrapped or protected edges are brought together and appropriately joined into a manufacturers joint or seam, the resulting joint or seam is liquid-tight and leak-free.

Appropriate means for completing such a liquid-tight seam include adhesive or heat-sealing means, the latter particularly useful when working with heat-scalable coated fiberboard sheet material. The use of both adhesive and heat sealing in combination may also be employed.

Preferably, however, the raw ends of the fiberboard sheet at the manufacturers joint may be protected by utilizing an extension of one of the facing sheets of a corrugated fiberboard liquid-tight container blank (preferably that liner which will be internal to the finished package) and wrapping the liner extension around the rest of the corrugated fiberboard structure at the margin area which will become part of the manufacturers joint. Preferably, both liners extend beyond the corrugating medium and are brought together with adhesive, and the raw edge of one liner wrapped with the `extension of the other liner.

The above and other novel features of the invention will appear more fully hereinafter from the following detailed description when taken in conjunction with the accompanying drawings. It is expressly unrerstood that the drawings are employed for purposes of illustration only and are not designed as a definition of the limits of the invention, reference being had for this purpose to the appended claims.

Referring to the drawings, wherein like characters indicate like parts:

FIGURE 1 is a perspective view of a container to which the joint has been applied; 1 .FIGURES 2, 3, and 4 are sectional diagrammatic views with thickness greatly exaggerated showing successive steps for preparing one edge of the container blank for the joint;

FIGURES 5 and 6 are sectional diagrammatic views with the thicknesses greatly exaggerated, showing successive steps for preparing the other edge of the container blank for the joint;

FIGURE 7 is a sectional diagrammatic view showing the blank edges overlapped and bonded together, the thicknesses being exaggerated;

FIGURE 8 is a sectional view, greatly enlarged and more closely showing the finished joint as it would appear in section and taken substantially on the line 8 8 of FIGURE l;

FIGURE 9 is a sectional view of a modified joint; and

FIGURE 10 is an end view of a blank which can be used in the formation of a joint of FIGURE 9, the blank having the central portion broken away and thicknesses exaggerated.

Referring to FIGURE l, there is shown a container constructed generally along the lines of that disclosed in Loheed et al Ser. No. 449,597, filed Apr. 20, 1965, now Patent No. 3,341,104. Such container is of the unslotted type and constructed of corrugated fberboard, portions of which have been crushed to substantially solid board. The container comprises side panels 20* and 22, and end panels 24 and 26. The lower end of the container has been sealed and winglike side flaps, such as 28, have been bonded to the container side walls 24 and 26 in recesses formed by crushing the corrugated ibreboard into substantially solid board. The upper end is shown open, the side and end panels having closure extensions 30, 32, 34, and 36, which form a tubular extension beyond the score lines, such as 38 and 40 of the front and side panels 22 and 24. The side panel 24 has a crushed recess area to receive a side wing formed when the upper structure is sealed by folding the closure extensions 32 and 36 outwardly and the extensions 30 and 34 inwardly.

In order to form a manufacturers joint 41 between the edges of the blank from which the container is formed and between the portions 44 and 46 of the panel 22, the edge of portion 44 of the blank which comprises an inner liner or facing sheet 48 and an outer liner or facing sheet 50, with intervening corrugating medium 52, is formed with the end 54 of the corrugating medium disposed inwardly of the edges 56 and 58 of the liners 48 and 50, and the portion 60 of the liner 48 is substantially longer than the portion 62 of liner 50. To prepare the edge for jointing, the portion 62 of liner 50 is offset as at 63 in FIGURE 3, and bonded to the portion 60 of liner 48 as at 65 and the extended lip 64 is folded over the edge 58 and bonded to the portion 62 as at 66 to provide a structure as indicated in FIGURE 4.

The other edge of the portion 46 of the blank may likewise have its liners 50 and 48 extend beyond the edge 70 of the corrugating medium, the liner 48 extending a little further than liner 50, so that when the portion 72 is otset as at 73 and bonded as at 75 to the portion 74, as shown in FIGURE 6, the end edges may be approximately in alignment. In both FIGURES 4 and 6, the corrugating medium and its raw edges 54 and 70, respectively, are sealed in. The internal surface 76 of the liner 48 is coated within a thin layer of waterproofing thermoplastic or other barrier material, so that when the ends of the blank are brought together and bonded to form the joint 51, the internal coated surface is continuous and protects the paper liner 48 and the corrugating medium S2 completely from liquids in contact with the coated surface 76.

In practice, the joint will appear in section more like FIGURE 8, although proportions are still exaggerated, but less so than in FIGURES 2-7, inclusive. While the interval surface of the liner 48 is completely protected against liquid by the barrier coating 76, the three raw edges 80 of the portions 74, 72, and 64 are exposed. Since these edges are on the outside of the container, they may not be subject to deterioration except by possible condensate or atmospheric moisture.

In order to completely seal the brous material of the line'rs 48 and 50 at the joint, both externally and internally, the two ends may be constructed similarly to that indicated in FIGURES 2-4, inclusive, but more precisely as indicated in FIGURE 9.

As shown in FIGURE 9, the ends of the corrugating medium 52 end at 54 and 70 as before, and are completey enclosed by the extended edge portions 82 and 84 of the liners 48 and 50, the extended portion `82 being longer than 84, and being folded over the portion 84 as at 86. The contacting surfaces are adhesively bonded as at 88 and 90. While the portion 84 is shown as offset inwardly as at 92, the portion 82 could be offset outwardly if desired, or both extended portions offset toward one another. Similarly, the edge portions 94 and 96 of the other edge of the blank are extended beyond the end 70 of the corrugating medium, and one or the other offset as at 98 to bring the extended portions 96 and 94 together, the two portions being adhesively bonded as at 100. The portion 96 is longer than the portion 94, and folded around the edge of the portion 94 as at 101, and bonded to the portion 94 as at 102.

The edge portions, after preparation in the manner described, are brought into overlapping relationship as shown in FIGURE 9, when the blank is formed into a 4 tube, and adhesive is applied to the surfaces 104 and 106, and the joint completed as indicated in FIGURE 9 by applying pressure until the adhesive has set or the bond is complete.

From the foregoing, it will be seen that if the liners 48 and 50 are each provided with a waterproofing barrier coating as at 110 and 112, the procedure set forth provides complete protection to the raw edges such as 114 and 116 or 118 and 120. The edges 114 and 118 are protected by the folding over the portions 86 and 101, while the edges 16 and 120 are protected when the joint is completed. A small space between the edges 116 and 120 in the final forming of the joint is provided to assure that the folded portions 86 and 101 will be in spaced abutting relation Without danger of their overlapping one another in the formation of the joint, since any overlay would likely defeat the purpose of the structure and result in a buildup in excess of the ve layers of paperboard at the joint, and result in unevenness. The joint thus formed en closes the raw edges of the paperboard, and by reason of the barrier coating inside and out, deterioration of the fibrous structure is prevented.

The preparation of the edge formations as indicated in FIGURES 2-4, FIGURES 5 and 6, or the formations in FIGURE 9, are readily effected by forming guides disposed along the conveyor, and the application of adhesive is similarly applied as the corrugated board is conveyed from the corrugating apparatus. Where the utes of the corrugating medium extend at right angles to the joint, the selection of liner stock and corrugating medium stock of proper width, with the liners oifset as is indicated in FIGURE 10, will result in tbreboard ready for the prepiaration of the edge formations.

The barrier coatings on the outer faces of the liners, if thermoplastic, may through the use of heat act as the adhesive, where such coated surfaces are brought together. For example, the contacting surfaces of portions l64 and 72, as in FIGURE 8, or as at 104 and 106 in FIGURE 9, if thermoplastic, may be heat sealed together.

In the form shown in FIGURE 8, the raw edges at may have a bead of barrier material applied to seal the raw edges, if desired. In such case, if the outside surfaces of the liners 48 and 50 are both treated with barrier material for waterproofing, all of the fibrous material of the breboard will be protected inside and out, as is the case with the modification of FIGURE 9.

While a single form of the invention with modifications has been illustrated and described, it is to be understood that the invention is not limited thereto. Various changes maybe made without departing from the spirit of the invention, as will be apparent to those skilled in the art.

What is claimed is:

1. A fluid impervious manufacturers joint formed `at the joining of ends of a corrugated tbreboard liquid-tight container blank, said uid impervious seam being comprised of an inner blank-end member and an outer blankend member, said inner blank-end member being comprised of breboard having one extended facing sheet wrapped around the rest of the `ibreboard structure at said inner blank end, the fluid impervious seam being formed by the folding and bringing together and lap joining of said inner and outer blank-end members.

2. A fluid impervious seam according to claim 1, in which both the inner blank-end and the outer blank-end members feature an extended facing sheet wrapped around the rest of the iibreboard structure at their respective areas, said wrapped end areas functioning to provide uid imperviousness in the joined and completed seam.

3. A fluid impervious seam according to claim 1, in whichthe extended facing sheet wrapped around the rest of the breboard structure at its coextensive end is the facing sheet positioned at the interior of the liquid-tight container.

4. A uid impervious seam according to claim 2, in which the extended facing sheet wrapped around the rest of the fibreboard structure at each coextensive end is the facing sheet positioned at the interior of the liquid-tight container.

5. A fluid impervious seam according to claim 2 formed at the joining of ends of a corrugated iiberboard liquidtight container blank, wherein said liquid-tight container blank is provided with a fluid impervious barrier coating on at least one of its facing sheet exteriors.

6. A fluid impervious seam formed at the joining of the opposite ends of a corrugated fibreboard liquid-tight container blank, said fluid impervious seam being comprised of an inner blankend member and an outer blankend member, the inner blank-end member having exible plastic packaging lm afxed by suitable means along and wrapped around said blank end margin, the fluid impervious seam being formed by the folding and bringing together and joining of said inner and outer blank-end members.

7. A fluid impervious seam according to claim 6, in which said wrapped-end edge of the liquid-tight container blank is reduced to a thickness not greater than one-half of the thickness of the original corrugated board.

8. A fluid impervious seam according to claim 6, in in which both inner and outer blank-end members have flexible plastic packaging film aflixed by suitable means along and wrapped around said coextensive blank-end margins, the wrapped end margin areas functioning to provide uid imperviousness in the joined and completed seam.

9. A fluid impervious seam according to claim 8, in which said wrapped-end edges of the liquid-tight container blank are reduced to a thickness not greater than one-half of the thickness of the original corrugated board.

10. A iuid impervious seam according to claim 2 wherein said corrugated fibreboard liquid-tight container blank comprises conventional uted paper-board center structure adhesively united to facing sheets over its entire area coextensive to the extended facing sheet at the edge margin of the liquid-tight container blank.

11. A uid impervious seam according to claim 1, wherein said corrugated ibreboard liquid-tight container blank comprises conventional fluted paperboard center structure adhesively united to facing sheets over the major portion of its area, and wherein the inner land outer facing sheets extend beyond the center structure at said inner blank end, the extension of the inner facing sheet begin approximately double the extension of the outer facing sheet to permit wrapping of the inner facing extension over the outer facing extension.

12. A fluid impervious seam according to claim 2, wherein said corrugated breboard liquid-tight container blank comprises conventional uted paperboard center structure adhesively united to facing sheets over the major portion of its area, and wherein the inner and blank-end members extend beyond the center structure and the extension of the inner facing sheet at each end is approximately double the extension of the outer facing sheet, and the inner facing extension is wrapped over the outer facing extension, and wherein a duid impervious seam is formed by the folding and bringing together and joining of said inner and outer blank-end members, said impervious seam having a cross-section thickness not greater than the thickness of the corrugated breboard comprising the said major portion of its area.

13. A manufacturers joint for a waterproof corrugated breboard container constructed of a blank of corrugated breboard having spaced liners and corrugating medium therebetween, said blank having overlapping joint ends, each end of which comprises inner and outer liner portions extending beyond the corrugating medium, with at least one liner portion offset into contact with the other over a substantial area and adhesively secured thereto, the inner liner portions of the inside lapping end being longer than and wrapped around the outer liner of the inside lapping end and overlying and adhesively secured over a substantial area of the other side of said outer liner, and said inner liner portion of the other end being adhesively secured to said overlying portion of the inner liner of the inside lapping end.

14. A joint according to claim 13, wherein the inside surface of the inner liner is coated with a thermoplastic barrier, and the adhesion between the overlying portion and inner liner portion of the other end comprises a heat seal.

15. A joint according to claim 13, wherein the overlying portion covers not more than half of the outer liner, and the outer liner portion of the other end is longer than and wrapped around the inner liner portion and overliesand is adhesively secured to the inside surface of the inner liner portion over an area not greater than half, and wherein the last-named portion that overlies the inner liner is adhesively secured to the uncovered area of the outer liner of the inside lapping end.

16.A joint according to claim 15, wherein both the inside surface of the inner liner and the outside surface of the outed liner are coated with a thermoplastic barrier, and wherein the adhesion between the overlying portion of the -inside liner and the other portion of the inside liner, and the adhesion lbetween the portion that overlies the outer liner both comprise heat seals.

References Cited UNITED STATES PATENTS 1,101,928 6/1914 Hawkins et al. 1,417,776 5/ 1922 Shafer 229-48 XR 1,617,274 2/ 1927 Romer 229-48 XR 1,698,908 1/ 1929 Cleveland 229-48 1,731,111 10/ 1929 Romer 229-48 2,795,366 6/ 1957 Magill. 3,081,213 3/1963 Chinn. 3,145,131 8/1964 Finke 229-48 XR 3,341,395 9/1967 Weber 161-133 DAVIS T. MOORHEAD, Primary Examiner U.S. Cl.X.R. 161-133 

